jmezo

Had the shaky steering wheel @ 50-65 MPH. I remember this happened to my other car after the brakes were inspected. The tech put the rim on without cross tightening the lug nuts.
Anyway I took off the wheel and noticed the brake rotor was not lined up with lug bolts. In other words the bolts were not centered on the holes of the brake rotor. So I broke the rotor free and lined up the holes. Put the wheel back on and now no shakes at 50MPH. I do get just a little of shake on braking at high speed but thats all.
I think the rotor can get stuck on the edge of the bore and not able to seat firmly on the spindle.

Hope this could help if you are having the same problem.

iolmaster

iTrader: (1)

I have been doing brakes my whole life. (60 now) and I have never paid any attention to aligning the holes. I never saw the need. They are always very tight. It was always my experience that the hub center, centered the rotor. I have never had any shakes. Hard to believe that was the problem.

jmezo

If the rotor bolt hole is riding on the fillet of lug bolt then it will not be completely seated on the spindle axially nothing to do with radial seating on the hub.

iolmaster

iTrader: (1)

If the rotor is not seated properly you would know immediately. The wheel would come loose right away.

momssc

this makes no sense. not the vibe problem

jmezo

I made a drawing of this to show what Im talking about. The drawings shows exaggerated condition. Brake parts are not precision parts and there is enough slop between mating parts that if the lug nuts are not tightened correctly ( the wheel is placed on the hub and only one nut is fully impact wrench tightened and then rest of the nuts are then added to the wheel and tightened can cause the brake rotor to be wedged on the spindle. And if its wedged on the spindle it would not come loose right away because its put on with impact wrench force. If its wedged it will have a very slight axial runnout. I had this happen to my RX300. I watched the dumb *** put my wheel on after a state inspection this way and when I drove off and got up to 60MPH on the expressway I could t figure out why I was getting steering wheel vibration right after the inspection. I went home and removed the wheel he put on. Looked at the brake drum and sure enough the drum was wedged on the spindle. When I got the SC had the shakes at 50~60 MPH and remembered my RX experience. I removed the front passenger wheel and the brake drum bolt holes were lined up with lug bolts. A small tap on the rotor and the rotor easily broken free from the spindle. OK then I removed the driver side and the rotor was bolt holes were not lined with the lug bolts! I gave the rotor a little tap and it was not coming loose from the spindle. I had to use the jack screws to pop it off the spindle. Now it was free to go back on the spindle I made sure bolts lined up with the rotor holes before putting the wheel back on.
The blue part is the spindle and the brown part is the brake rotor.

jmezo

Front of assembly with holes not aligned.

iolmaster

iTrader: (1)

The rotor is centered by the hub at the end of the drive shaft, not the lugs. Your drawings do nothing more than convince me that the rotor being positioned as you describe is not the problem.

Bon

I think that the OP's point is that the brake disc center hole is too large for a proper and tight fit on the hub. If that is the case, and the lug stud holes are also oversize (and the probably are) then the rotor could be mounted off center and act as an eccentric weight. On the other hand if the brake disc center hole is correctly sized for a good hub centric fit then the lug stud holes may be rotated off center as shown in the drawing but not result in an eccentric weight. So it all seems to come down to the sizing and tolerance of the rotor hub. Just like hub centric wheels, too loose is bad. And, it sounds as if Jmezo's hub centric rotors are not a good fit for his hubs. Our lug nuts aren't cone shaped because our wheels are hub centric. Hub to rotor to wheel sizing must be tight. This is a link to some rotor centering rings. No, not for Lexus but you get the idea.
https://www.rtmracing.com/xcart/prod...roductid=16602

jmezo

Yes the rotor is positioned radially by the hub. If the nuts are jammed on with interference by the lugs then the rotor is not seated to the spindle axially. OK I'm done with this.

I had a problem with steering wheel shake and did nothing more than brake the rotor free and put it back on correctly and now I don't have steering wheel shake.

So I pass this information on to the group. I didn't have my tires re balanced 3 times and I didn't put new tires on or wheel alignment or bushings on or tie rods... I did this and it worked for me.

The previous owner could not get the shakes out of this car and sold it to me and now I have car with new tires bushings (provided by the previous owner)... with only 38K miles on it and now drives as smooth as glass.

Bon

Please don't get frustrated as you try to clarify the issue you've had and what fixed it. Many here have had front end shakes with their SC and have spent plenty of time and money trying to resolve it. Another insight into the problem is always welcome.

sorka

I've been doing my own brakes on a dozen+ cars for 20+ years. I do not see how this could have caused the problem. It's much more likely something was trapped between the rotor and the seat and that it came lose when you removed the caliper.

Also, do you have wheel locks? If so, does the lock lug weigh exactly what the regular lugs weigh?

MrMark

iTrader: (3)

I just like the pictures.....once bolted down, this should not cause any vibrations. You may want to balance the wheels too.

jmezo

Did not remove the rotor to clean it. Just broke it free and re installed wheel. I dont use lock nuts on my cars.
As I said this problem also happened to my RX300 after the tech put on the wheel and put one nut on and impact tightened it fully!!! then put the rest of the nuts on. I drove away and had instant steering wheel shake.

tromly

same thing happened to me!